intervention weeks 1-12 the subjects in each group will be counseled to follow their weight maintaining assigned diet using a combination of prescribed menus (breakfast, lunch, and snack eating occasions) and an item specific version of the Pasta Recipe Builder (dinner). The two group-specific diet plans will mostly contain the same foods and beverages typically included in Mediterranean-style diets, except for substitutions of major sources of carbohydrate in their meals:Low-GI - pasta, barley, parboiled rice, legumes.

intervention weeks 1-12 the subjects in each group will be counseled to follow their weight maintaining assigned diet using a combination of prescribed menus (breakfast, lunch, and snack eating occasions) and an item specific version of the Pasta Recipe Builder (dinner). The two group-specific diet plans will mostly contain the same foods and beverages typically included in Mediterranean-style diets, except for substitutions of major sources of carbohydrate in their meals: Hi-GI - rice, potato,

subjects will consume the same quantities of metabolizable CHOs (270 g/d) with 135 g of CHOs assigned to the GI intervention foods. The 135 g of CHOs will be distributed as 35 g GI breakfast product, 40 g GI lunch product, and 60 g GI dinner product. Assuming an average 2400 kcal/d total energy requirement among subjects, the 270 g/d metabolizable CHO equates to 40% of total energy intake (1080 kcal/d). One-half of daily CHO intake (135 g/d) will be the same between the Hi-GI and Low-GI groups, including CHOs in fruits, vegetables, and other foods that all subjects will consume. The other one-half of daily CHO intake (135 g) will be different between the Low-GI and Hi-GI groups. Specifically, the GI values of these foods will either be <55 (Low-GI group) or >70 (Hi-GI group).

All subjects will consume the same quantities of metabolizable carbohydrate (270 g/d) with 135 g of carbohydrates assigned to the GI intervention foods. The 135 g of carbohydrates will be distributed as 35 g GI breakfast product, 40 g GI lunch product, and 60 g GI dinner product. Fiber is set as 35 g/d for both intervention groups. Assuming an average 2400 kcal/d total energy requirement among subjects, the 270 g/d metabolizable CHO equates to 40% of total energy intake (1080 kcal/d). One-half of daily CHO intake (135 g/d) will be the same between the Hi-GI and Low-GI groups, including CHOs in fruits, vegetables, and other foods that all subjects will consume. The other one-half of daily CHO intake (135 g) will be different between the Low-GI and Hi-GI groups. Specifically, the GI values of these foods will either be <55 (Low-GI group) or >70 (Hi-GI group).

Measures of Insulin Sensitivity will include fasting serum lipid-lipoprotein profile, plasma fasting and postprandial glucose, insulin, CRP, C-peptide, fasting HbA1c, 24-hour interstitial continuous glucose monitoring (Medtronic ipro2 Professional CGM device (Northridge, CA).